Major energy users on Australia’s east coast shut down Friday, and residents were asked not to go home and cook or watch television to ease demand on strained power supplies as an extreme heat wave moved from the desert interior to the coast.

Authorities were preparing to temporarily suspend power to selected areas of New South Wales (NSW) state late Friday to prevent overload just days after 40,000 homes and businesses lost electricity in the state of South Australia.

“Rather than going straight home and turning on the television and cooking, (you might) want to consider going to a movie, going out to a shopping center, keeping the load low, every bit like that helps,” Harwin told journalists in Sydney.

A paper mill, water treatment operations and Australia’s largest aluminum smelter, Tomago, were among those that halted operations to conserve energy, with many industrial users required to do so under their contracts.

Weather forecaster Olenka Duma said a build-up of heat in Australia’s interior was being pushed east across NSW, the country’s most populous state.

The mercury climbed to 40 degrees Celsius (104 degrees Fahrenheit) in parts of NSW and the Australian Capital Territory on Friday, while Saturday is expected to set a record for the hottest February day on record.

It was too hot for people to go out, said Ned Qutami, owner of six mobile ice cream bars in Sydney.

“I’m not doing any business today, I’m just sitting in the air-conditioning at home,” said Qutami, who runs Sydney Ice Cream & Coffee in the city’s beachside eastern suburbs. “People at the beach are either in the water or heading home. No one is hanging around to eat ice cream.”

No wind, no wind power

The intense heat and power outages have sparked debate over the country’s energy security, after the market operator told power companies in South Australia on Wednesday to switch off some customers’ power supply for a short spell to manage demand.

South Australia depends on wind for more than a third of its power supply, and the wind died down at the same time as people started cranking up air-conditioners.

That was the latest in a string of power disruptions and electricity price spikes to hit the southern state, including a statewide blackout that forced copper mines, smelters and a steel plant to shut for up to two weeks last September.

The problems have sparked a review of the national electricity market and energy policy on how to cope with rapid growth of wind and solar power and the closure of coal-fired power plants that have been essential for steady supply.